Cannabis seed breeders often refer to F1, F2, S1, IBL & BX marijuana seeds. Find out what the terms mean and how they evolved. It is not rare to see novice growers wondering what IBL, BX or S1 mean. While they may seem useless, these acronyms give plenty of information when we Reading about cannabis genetics can be confusing. In this article, we provide a comprehensive breakdown of common cannabis genetics and breeding terminology.
What are F1, F2, S1 cannabis seeds?
To many people cannabis seeds are simply cannabis seeds. But breeders and connoisseur growers also use different terms for cannabis seeds, such as F1, F2, S1 etc. In this review, we will explain what is meant by these terms and precisely what they tell you about the cannabis seeds which they describe.
|●||The basics of cannabis genetics for breeders|
|●||Different types of F1 cannabis seeds|
|●||The difference between F1 and F2 cannabis seeds|
|●||How does selfing produce S1 cannabis seeds?|
|●||Cannabis genetics hybridisation process case studies|
|●||Cannabis seeds quality: what to know before growing?|
The basics of cannabis genetics for breeders
Most home growers tend not to worry too much about terms such as F1 cannabis seeds, F1 hybrid cannabis seeds etc. So long as the seeds contain reliably good quality genetics few people are too concerned about the terminology used. However, to many cannabis breeders it is vitally important to understand the sometimes subtle, but critical, differences.
What does f1 hybrid mean? Cannabis seeds are formed when pollen from the male pollinates a female plant. The male genetics cross with those from the female to create F1 cannabis seeds, meaning that the cross is a First generation cross. If the parents were from two different strains the result would be F1 hybrid cannabis seeds.
Note that male pollen spreads easily and will pollinate any nearby female plants. That’s why professional breeders have isolated, dedicated breeding rooms which prevent accidental pollen spread. Pollen may be applied with small brushes using e.g. paint brushes, allowing specific branches to be pollinated with pollen from different males if required. Or male and female plants may share the same room, pollen is spread simply using air circulation fans.
Anyone involved with breeding/pollen would normally shower and change clothes to prevent unintended cross contamination between different areas of their breeding facility. Once pollinated, the female plant focusses much of her energy into seed production (rather than bud production).
What are F1 hybrid cannabis seeds?
F1 cannabis seeds simply mean that they are a first generation of offspring from the parent strains. Hybrid vigour is a term often used when discussing cannabis seeds, along with the question ‘Can an F1 outbreed for hybrid vigor?’ Cannabis hybrid vigour is observed when different strains are hybridised in an F1 cross.
If the parent strains were quite different indica and sativa strains then the seeds would be called F1 hybrid cannabis seeds, these may show vigorous growth and display ‘hybrid vigour’ resulting in growth which is faster than usual. This extra growth vitality is seen when different cannabis genetics are hybridised to create an F1 cannabis cross.
Different types of F1 cannabis seeds
F1 cannabis seeds explained! You can buy F1 autoflowering cannabis seeds or photoperiod F1 feminised cannabis seeds. Autoflower seeds tend to have a reputation for being faster and perhaps a little easier/more convenient than feminised seeds, but much depends on the preferences of the grower. F1 regular cannabis seeds are also popular with some old school growers or those conducting their own breeding experiments.
F1 fast cannabis strains are also available, with strains such as Think Fast. These strains have recessive autoflower genetics which cause the f1 fast cannabis strains to grow from seed to harvest a couple of weeks faster than traditional strains. For some outdoor growers this could be the difference between a harvest which ripens before the bad weather arrives and one which doesn’t.
Many connoisseur growers prefer to buy genuine F1 cannabis seeds in order to get the highest chance of the consistent quality results which are most similar to the parent strains. F1 White Widow cannabis seeds from Dutch Passion are a good example. The large numbers of repeat White Widow growers know that their best chances of producing original Grade-A White Widow buds is to use F1 White Widow cannabis seeds.
The difference between F1 and F2 cannabis seeds
F1 cannabis seeds are produced when two parents are crossed. When you see F1 cannabis seeds for sale you would normally expect them to show the closest qualities to the original strains. When the F1 cannabis seeds are grown and subsequently crossed the resulting seeds are known as F2 cannabis seeds.
The subject of F1 and F2 cannabis genetics can be a complicated subject, with questions such as ‘is F1 better than F2 cannabis?’ Whether you get better results with F1 vs F2 cannabis seeds will depend on the individual phenotypes being grown, as well your definition of the word ‘better’. It is perhaps safest to say that F1 cannabis seeds are more likely to show results closer to the original parents compared to F2 seeds.
Note. Growing and crossing F2 cannabis seeds would produce F3 cannabis seeds.
What are inbred line cannabis seeds (IBL)?
Inbred line cannabis seeds, often known simply as IBL seeds, are the result of inbreeding the descendants of the F1 cannabis seeds. It is usual to breed for 5 or more generations (F5) in order to be regarded as inbred line cannabis seeds. At this point the IBL may often be considered as a distinct strain in its own right.
Remember that the cannabis seeds have been produced from plants with genetics which are practically identical over several generations. Although this type of breeding is arduous and may take several years, the resulting cannabis seeds are typically very consistent with highly predictable results for the grower.
The Skunk family of cannabis seeds is an example of in-breeding which has allowed the successful preservation of the distinctive skunk aroma and taste.
What are poly-hybrid cannabis seeds?
The most reputable cannabis seed suppliers work hard to identify the best genetics and then stabilise them, a process which sometimes takes several years. Stable consistent cannabis seeds give the grower the best chance of replicating premium quality genetics in their own grow room. However, if two (F1) hybrid strains are crossed the result is poly hybrid cannabis seeds.
When growing such seeds you can reasonably expect any of the genetics from the diverse parentage to be expressed. For some growers, variety is a good thing. For other growers seeking a tent full of consistent/uniform plants, poly-hybrid cannabis seeds are unwelcome guests.
Many of the less experienced seed suppliers intent on making a ‘fast buck’ simply cross male and female plants to create rapid seed production with absolutely no thought given to stabilisation or optimisation of the genetics. Be sure to do your research carefully before buying cannabis seeds and choose seed banks with a good track record of customer service, plenty of repeat customers and perhaps a few cannabis cups. Cannabis cups are usually a sure sign that your seed bank takes their profession seriously and is there for the long haul.
|Dutch Passion cannabis cup winning strains|
How does selfing produce S1 cannabis seeds?
What does F1 and S1 mean? Female cannabis plants can produce S1 cannabis seeds through a process known as ‘selfing’. Usually this involves taking a cutting/clone from the female mother plant and turning it into a male by a process known as ‘reversion’.
This can be done by spraying the female with a chemical such as Silver Thiosulphate. The stress of this causes the female to become a male plant. Pollen is then collected from this plant and used to pollinate the original mother plant. This allows the original female to effectively be ‘self-pollinated’ or ‘selfed’. The cannabis seeds are known as S1 seeds and have the added stability benefit of using the ‘same’ genetics from the male and female.
Cannabis genetics backcrossing explained
When two parent strains are crossed the result is an F1 cannabis seed. If this seed is grown and crossed with one of the original parents, it is known as backcrossing. Backcrossing is a way of stabilising a cannabis strain since it allows parent genetics to be backcrossed with genetically similar offspring. As a result, greater genetic stability is conferred on the resulting cannabis seeds. This produces more consistent seeds with more predictably uniform results in your grow room.
Cannabis genetics hybridisation process case studies
Often cannabis breeders will aim to combine two great qualities from different strains into a new hybrid. Often this will involve e.g. taking the cannabinoid content from one strains and augmenting it with XXL yields from another.
Orange Hill Special
Orange Hill Special is a Dutch Passion photoperiod feminised seed variety. She was in-bred over 6 generations after the initial crossing with genetics from Orange Bud and Californian Orange.
Orange Bud and Californian Orange are both members of the multi-cannabis cup winning Orange Family of cannabis seeds. These strains stand for premium quality harvests of beautifully citrus scented buds. Orange Bud and Californian Orange have slightly different but complementary terpene profiles. The aim of the hybridisation was to combine the best features of each variety into a new stable strain which would embody the best taste, THC levels and yields.
Orange Hill Special is a member of the most potent cannabis seed selection available, the High THC cannabis seed collection. This is where you can expect consistent 20-25% THC levels across all plants when grown in good conditions. Such stability and consistency don’t arrive by accident, it’s the result of several years of careful selection, lab analysis, stabilisation and careful breeding. If you’re looking to grow heavy harvests of extremely THC rich citrus scented skunk buds then Orange Hill Special is a perfect choice. For best results, LED grow lights are recommended.
Basic nomenclature of cannabis genetics
Often, when it’s time to buy cannabis seeds, the beginner grower can quickly become confused by some of the acronyms that are written next to the name of the variety. Simply by learning some basic concepts you’ll be able to make the correct choice between seeds with the same name, but different acronym.
There is a big difference between acquiring a second filial generation (F2) or an IBL, even if we talk about seeds of the same variety. These differences will condition the growth pattern of the plants, and also the final product, so that it is almost essential to learn exactly what is the meaning of these acronyms to be more accurate in choosing which seeds to buy, saving ourselves deceptions and getting closer to our preferences.
Also known as landraces or purebreds, pure cannabis varieties have been the basis of cannabis breeding over the past decades. These species are endemic to a geographical area, where they have developed without having been crossed (hybridised) with other varieties. There are a large number of landraces from all around the planet, belonging to any of the three families of cannabis, C. sativa, C. indica and C. afghanica. Nepal is a good example; in this country different pure cannabis varieties (mostly narrow-leaved mixed use varieties) are grown and you can easily see the differences between genotypes based on the height above sea level at which they are cultivated.
Each variety expresses its genetic code (genotype) with a certain growth and flowering pattern (phenotype), so that pure varieties – with a purest genotype – show great uniformity, with just a few slight differences between phenotypes. We can expect very little variation between landrace specimens of the same variety, giving plants with very similar growth, organoleptic and psychoactive traits. Good examples of these varieties can be Hindu Kush (Sensi Seeds), Colombia Punto Rojo (Cannabiogen) or China Yunnan (Ace Seeds).
IBL or stabilized cannabis hybrids
The IBL acronym (in-bred line), means that the cross was made using plants with almost identical genotype (inbreeding). On the contray, outbreeding is employed to introduce new genes into the variety. Although it happens naturally, self-pollination is a common technique used by breeders to fix desirable traits and thus stabilise the genetic line, either with landraces or hybrids. In cannabis genetics IBL seeds should present a highly uniform growth. Classic IBL examples are Skunk and Northern Lights (Sensi Seeds) or White Widow (Greenhouse). There is a lot of work behind IBL’s like these, as a large population of pure specimens had to be used to select the correct parents. In addition, the breeder must fight against inbreeding depression, the result of crossing parents with very similar genetic information. The reward for this job made properly is a highly stable seed variety.
If we make a cross between two different landrace or IBL lines (parental A and B) with different genotypes, the resulting offspring will be the F1 hybrid, the first filial generation from the cross of the phenotype #1 (Parent A) with the phenotype #2 (Parent B). Commonly in this kind of crosses we will observe a very uniform offspring, depending on how stable the parents are, of course. The F1 hybrid between two pure varieties or IBL’s will show the so-called hybrid vigour – also known as heterosis or outbreeding enhancement – introducing new genes that will produce “better” specimens.
Varieties like Orient Express (Ace Seeds), Red Afro (Tropical Seeds) or Eddy from Original Delicatessen would be good examples of true F1 hybrid. Thus, we refer to the first filial generation of any cross as an F1, while the term “F1 hybrid” is used when the parents are different landrace or IBLs.
How to create a polyhybrid
When we cross two F1 individuals (whether landraces, hybrid or polyhybrid varieties), we obtain the second filial generation or F2, and so on with next generations, F3, F4, etc. The second filial generation often gives a more heterogeneous offspring than the F1; we can expect 25% to resemble parent A, 25% to resemble parent B and 50% will be a mixed expression of traits from both parents. As a consequence the stabilisation work must continue generation after generation ( F3, F4, F5…) until we find the generation that gives a uniform offspring with the traits that we are seeking.
Many of the seeds that we can find in shops are polyhybrids, crosses between different hybrids. The offspring of such crosses are in many cases quite unstable, producing plants with very different traits. Keep in mind that in these cases, the genetic mix is very varied, so we can not expect polyhybrid offspring to be as homogenous as an F1 hybrid. It’s easy to imagine how complex it can be to stabilise a cross, since we are mixing different genes from different varieties, which makes the selection and stabilisation process of the different traits a very hard work. The vast majority of hybrids on the market are in fact polyhybrids, like the White Russian (Serious Seeds) or Fruity Jack / Jack el Frutero (Philosopher Seeds).
BX or Backcross
Backcrossing is a common technique used by breeders to fix certain traits. This is done by crossing one of the progeny (F1, F2…) with one of the original parents (recurrent parent) which has the desired trait. To have an even more stable expression of the desirable trait, you can cross the BX1 again with the recurrent parent to have a BX2 (squaring) and so on with BX3 (cubing), BX4, BX5.
This technique is also used to replicate clones in seed form. It is done by choosing a male parent to cross with the clone only, backcrossing it as many times as needed to get an offspring as similar as possible to the original clone. The Apollo 13Bx (TGA Subcool) is an excellent example of this technique.
Tropimango by Philosopher Seeds
S1, feminised cannabis seeds
The acronym S1 refers to the first filial generation produced as a result of crossing the plant with itself. This is achieved by a range of techniques aimed at reversing the sex of the selected female plant, getting it to produce male pollen and using it to pollinate itself. If it’s done properly, we get feminised offspring with the same genotype of the parent used.
As always in genetics, the more stable the parent is, the more stable the offspring will be. This technique can also be used as a regular backcross, selecting and fixing traits but starting with just one parent. Thus, we can find S2 or S3 seeds, which have been backcrossed again with the original parent. Examples of S1 are Tropimango (Philosopher Seeds), S.A.D. (Sweet Seeds) or Trainweck (Greenhouse).
The articles published by Alchimiaweb, S.L. are reserved for adult clients only. We would like to remind our customers that cannabis seeds are not listed in the European Community catalogue. They are products intended for genetic conservation and collecting, in no case for cultivation. In some countries it is strictly forbidden to germinate cannabis seeds, other than those authorised by the European Union. We recommend our customers not to infringe the law in any way, we are not responsible for their use.
Understanding Cannabis Genetics Terminology
Reading about cannabis genetics can feel overwhelming. Use this list of common cannabis genetics and breeding terms to better understand words like phenotype, genotype, backcrossing, and much more.
Cannabis cultivation, cannabis history, cannabis culture
Cannabis Breeding – Genetics – Tissue Culture – Quality Control
- Understanding cannabis lineage
- A note on hemp
- Cannabis phenotype vs genotype: example
- Chemovar / chemotype / cultivar / strain
- Purebreds and landraces
- Heirloom varieties
- Inbred lines (ibls)
- F1 hybrid
- Poly hybrids
- Backcross (bc)
Cannabis is an ancient plant that has accompanied humans for thousands of years.
Today, thousands of cannabis varieties exist, and breeders around the globe continue to add to the tally. To help you understand what goes into creating the varieties you love most, we’ve created this handy list of cannabis genetics terminology.
Understanding Cannabis Lineage
Cannabis falls into the category of a dioecious plant. This means that individual plants have either male or female reproductive organs, not both. Female plants grow flowers that develop glandular trichomes—structures that produce phytochemicals such as cannabinoids and terpenes. Male plants possess small sacs that release pollen to fertilise female plants.
However, cannabis plants can sometimes be monoecious, meaning both male and female sex organs emerge on the same plant. This occurs due to either genetic or environmental factors, and ultimately allows a plant to fertilise itself. Known as hermaphroditism, it serves as an impressive reproduction mechanism for stressed plants, yet most growers try to avoid this phenomenon as it causes their flowers to produce seeds.
Cannabis is a genus of flowering plants belonging to the Cannabaceae family (which also comprises hops and other plant species). While cannabis grows all over the world, it is believed to originate from Central Asia, which is also likely where it was first domesticated.
Besides being dioecious, cannabis plants can be further divided into three distinct subspecies; Cannabis sativa (C. sativa subsp. sativa), Cannabis indica (C. sativa subsp. indica), and Cannabis ruderalis (C. sativa subsp. ruderalis), all of which have unique traits:
Cannabis sativa These plants originate from warmer, tropical climates. They typically have longer flowering times and grow taller with large internodal spacing. Sativas tend to produce large, airy buds that can stand up to warm, humid conditions. Cannabis indica Indicas originate from colder regions in Central Asia and the Indian subcontinent. They grow shorter and bushier, have shorter flowering periods (as they adapted to the shorter summers in these regions), and typically produce more dense buds than sativas. Cannabis ruderalis Discovered in Russia in the 1920s, ruderalis plants grow very small, typically reaching maximum heights of 60cm, and develop thin, slightly fibrous stems with few branches and flowers. Unlike Cannabis sativa and indica, which flower based on changes to their photoperiod, ruderalis plants begin to flower automatically once they are about 4 weeks old.
These plants originate from warmer, tropical climates. They typically have longer flowering times and grow taller with large internodal spacing. Sativas tend to produce large, airy buds that can stand up to warm, humid conditions.
Indicas originate from colder regions in Central Asia and the Indian subcontinent. They grow shorter and bushier, have shorter flowering periods (as they adapted to the shorter summers in these regions), and typically produce more dense buds than sativas.
Discovered in Russia in the 1920s, ruderalis plants grow very small, typically reaching maximum heights of 60cm, and develop thin, slightly fibrous stems with few branches and flowers. Unlike Cannabis sativa and indica, which flower based on changes to their photoperiod, ruderalis plants begin to flower automatically once they are about 4 weeks old.
A Note on Hemp
People often confuse hemp as a separate species of cannabis. However, hemp is just a term used to refer to cannabis varieties that have been bred for industrial purposes, such as to produce fibre for textiles. Hemp plants typically have very low concentrations of THC and produce big, thick stems and few branches.
Understanding Cannabis Genotype and Phenotype
The difference between genotype and phenotype is a fundamental concept you need to wrap your head around in order to properly understand cannabis genetics.
Genotype This refers to a cannabis plant’s genetic composition, or the combination of genes passed down from its parents. These genes serve as a code for the potential traits a plant might express, including characteristics such as height, internodal spacing, colour, and leaf shape. Overall, think of genotype as the instructions for all of the potential traits a plant could develop based on the genetic information inherited from its parents. Phenotype Whereas genotype is all about genetic instructions, phenotype refers to the combination of traits a plant actually expresses as it grows. Phenotype is influenced by both genetic and environmental factors.
This refers to a cannabis plant’s genetic composition, or the combination of genes passed down from its parents. These genes serve as a code for the potential traits a plant might express, including characteristics such as height, internodal spacing, colour, and leaf shape. Overall, think of genotype as the instructions for all of the potential traits a plant could develop based on the genetic information inherited from its parents.
Whereas genotype is all about genetic instructions, phenotype refers to the combination of traits a plant actually expresses as it grows . Phenotype is influenced by both genetic and environmental factors.
Cannabis Phenotype vs Genotype: Example
Genotypes are determined by the genes a plant inherits from its parents. Each gene can present two or more alleles, which are variant forms of a gene that differ in DNA sequence and carry information that code for different traits. The children of a human couple, or seeds of a plant, can carry different alleles despite having the same parents. For example, two children born of the same parents may have a different eye colour. The same applies to cannabis seeds. After crossing a female with a male, breeders end up with seeds that possess genetic variations.
As an example for growers, two seeds from the same parents have two different genotypes. This means they’ll display slightly different traits even when grown under the exact same conditions.
How does this differ from a phenotype? Well, phenotype describes how a plant looks and behaves; i.e. how the genotype interacts with the environment to determine a plant’s traits.
Let’s say you’ve just sown a packet of seeds from the same parents. Throughout the growing cycle, you treat them all exactly the same. You give them all the same soil, nutrients, water, pot size, and light exposure. Despite the strict environmental conditions, you’ll still notice subtle differences between each plant come harvest time. That’s because each of them features a distinct genotype.
Many breeders use phenotype selection to produce new strains. By selecting the plants that grow the best in the same environment, they can tease out desired traits over subsequent generations. Remember, a phenotype depends on both genes and the environment, not genes alone. Therefore, even clones (which share the same genotype) can develop different phenotypes based on external conditions. For example, placing two different cuttings from the same plant at different distances from a light source will affect their height.